Recently, the performance and functionality of digital cameras and digital movie cameras that use some solid-state image sensor such as a CCD or a CMOS (which will be sometimes simply referred to herein as an “image sensor”) have been enhanced to an astonishing degree. In particular, the size of a pixel structure for use in an image sensor has been further reduced these days thanks to rapid development of semiconductor device processing technologies, thus getting an even greater number of pixels and drivers integrated together in an image sensor. As a result, the resolution of an image sensor has lately increased rapidly from around one million pixels to ten million or more pixels in a matter of few years. While the performance of an image sensor has been further enhanced, new functions have recently been added one after another. For example, a polarization imaging camera which can obtain two-dimensional polarization information by arranging a polarization filter on each pixel of an image sensor has been developed just lately.
In a polarization imaging camera, an array patterned polarizers is arranged in front of the image sensor. Based on the luminance values of multiple proximate pixels, polarization information about the principal axis direction, average luminance and polarization component intensity of polarized light can be obtained.
Ordinarily, a polarization imaging camera can obtain only a monochrome image. Thus, to obtain a color image using a polarization imaging camera, a color filter needs to be arranged over each pixel of the image sensor. For example, in the image capture devices disclosed in Patent Documents Nos. 1 and 2, a plurality of patterned polarizers and a plurality of color filters that are arranged in a mosaic pattern are stacked one upon the other over a plurality of pixels of the image sensor. As a result, polarization information and color information can be obtained at the same time.